Myriad Genetics’ RiskScore Accurately Identifies Breast Cancer Risk in Undiagnosed Women of All Ancestries

Myriad Genetics’ MyRisk Hereditary Cancer test with RiskScore® allows women of all ancestries who were previously undiagnosed with breast cancer to receive personalized polygenic breast cancer risk assessment, according to a press release from the test’s developer.¹

Results using the global polygenic risk scores (gPRSs) were presented during the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting and indicated the gPRS had a strong association with breast cancer in the full validation cohort and in sub-cohorts.² Findings from the study indicated that at least 95% of breast cancer single-nucleotide polymorphisms (SNPs) have a 1% of more frequency of risk alleles within patients of African (96%; n = 89/93), Asian (95%; n = 88/93), and Hispanic (98%; n = 91/93) ancestry. The GPRS demonstrated overall improved discrimination over the 86-SNP PRS with the exception of Asian populations, which had too small of a sample size to demonstrate superiority.

“The [PRS] is one of the most powerful risk prediction tools in the field of breast cancer, and until now a validated model had not been available to assess women of all ancestries,” Holly Pederson, MD, director of medical breast services at Cleveland Clinic, said in a press release. “Our data now provide a framework for a PRS that delivers a personalized genomic breast cancer risk assessment to any and all interested women. The updated PRS, validated and well-calibrated, may be the most exciting clinical development in risk stratification since multi-gene panel testing.”

MyRisk with RiskScore is designed to help improve patient outcomes while minimizing health care disparities, with results that are informed by a mix of genetic markers, clinical and biological variables, personal/family history, and ancestry data. According to the press release, RiskScore is available to any women who take a MyRisk test at no extra cost.

Although 95% of females will test negative for high-risk gene mutations with traditional hereditary cancer tests, they will often have other risk factors that still need to be managed. Over half of patients (56%) who receive a RiskScore result will qualify for medical management changes, including increased surveillance or intervention. The study incorporated data from more than 275,000 women who were used to validate the enhanced method for evaluating gPRS across all ancestries.

Ancestry-specific PRSs for the study corresponded to 3 continental ancestries that were developed from 149 SNPs. The African PRS was developed utilized self-reported African American patients who were referred for hereditary cancer testing (n = 31,126) and the East Asian PRS was developed utilizing Asia Breast Cancer Consortium data. Additionally, the European PRS was developed through the Breast Cancer Association Consortium and European hereditary cancer tests (n = 24,259).

Additionally, an independent validation cohort (n = 62,707) was evaluated for discrimination and calibration gPRS, the performance of which was compared against a previously described 86-SNP PRS for women of European ancestry.

“All women in the U.S. should have equal access to the insights that genetic testing provides. As a doctor, improving health outcomes has always been my mission. Women and the physicians whom they trust for guidance will now have access to an assessment tool that considers the unique genetic makeup of different ethnicities, providing vital information that can help save lives,” Monique Gary, DO, FACS, breast surgeon and patient advocate at Grand View Health, concluded.

References

1. Myriad Genetics expands access to genetic testing with launch of first polygenic breast cancer risk assessment score validated for women of all ancestries. News release. Myriad Genetics. August 2, 2021. Accessed August 3, 2021. https://bit.ly/3ylXU2l
2. Hughes E, Tiemeny P, Gallagher S, et al. Ancestrally unbiased polygenic breast cancer (BC) risk assessment. J Clin Oncol. 2021;39(suppl 15):10502. doi:10.1200/JCO.2021.39.15_suppl.10502